Dry hop questions will get you lots of opposing answers.
Start with this:
"Question=does it hurt to let the wort ferment more than 10 days after you have dry hopped?"
I know it is kind of a semantics thing, but the wort is done fermenting when all of the fermentable sugars have been consumed by the yeast. Given an appropriate sized pitch combined with a wort rich in nutrients and O2, for an Ale around ~1.050, fermentation will be done in about 3 days after pitching. A bigger beer, like your Stone IPA (with I believe is around 1.070) may take 4-5 days to complete fermentation. Something huge (> 1.100), like a RIS or an English Barley wine can still be fermenting as much as 7 days after pitching. Naturally, those timelines carry the caviat of a healthy pitch and a well controlled fermentation, so YMMV. After the (now) beer is done fermenting, it is a good idea to leave it on the yeast to allow for a conditing period. How long that conditioning period lasts is another point for debate. On the English Barley Wine style show, Jamil said he allows another 4 days after (a 7 day) fermentation for the yeast to clean up bi-products, then he racks to a keg. There is a very knowledgable brewer on this site named remilard who seems to follow a similar schedule to Jamil - something in the 10/12/14 day range, and does so with a great deal of success. It won't take much searching to find out that another member, Revvy, advocates a full month in the primary. Personally, I fall in the middle at 3 weeks in the primary before bottling - but I am willing to budge on that three week rule if my schedule requires it.
Now that the "fermentation" thing is out of the way, I can get back to the dry hop question.
The longer you leave the dry hop in the fermenter, the more of a vegetal or grassy flavor the beer will take on. Some people may like that "grassy" flavor, others may be offended by it. Personally, I am in the second group.
The biggest hurdle to a dry hop is the timing. If you add the hops as the yeast is still actively fermenting the beer, the positive pressure of CO2 being driven out of the carboy will detract from the hop aroma you are trying to obtain. Some pros try to time the dry hop at the very tail of fermentation, but I am simply not confident enough to pull off that timing. In addition, I leave my beer to condition in the fermenter longer than a production brewery, so if I do not hold off on the dry hop, the hops will be left in the beer for a longer time period prior to packaging than I am comfortable with.
That said, I use a 5 day maximum for dry hops. To be clearer, I know I am bottling on Sunday, so I will add my dry hop on the prior Wednesday. It may be obvious, but you count your dry hop days backward from when you plan to package. Some may say that 5 days is not enough time, but in my experience, 5 days, in the mid 60's F, is plenty of time for the hop oils to make their way into your beer, leaving a ton of aroma, and very little grassy character. If you found that after 5 days you did not get the aroma you wanted, then you have a recipe issue - bigger dry hop next time, not more days of contact at the same quantity. For an IPA, I would consider 2 oz / 5 gallons to be the minimum. I have an excellent APA recipe that calls for 4.5 oz / 5 gallons - yes you will lose some wort due to absorption, but account for it during the boil and the losses are a non-issue at packaging.
So will it hurt to dry hop 10 days? Certainly not, but it is worth experimenting a bit to see what kind of character you prefer. Maybe try making the same beer 3 times. Once with a 2 week dry hop, once with 10 days, and once with 5 days, and take it from there. I've done all three, and I like 5 days the best.
Joe
